The principal long-range objective of this program is to discover the integrative and regulatory interactions among the genetic and protein-synthesizing systems which comprise enkaryotic cells. These systems include the nucleocytoplasm and the energy-transducing organelles. The following specific problems are to be examined during this period: 1. the organization and information content of an organelle genome. 2. The structure, behavior and possible functional interrelationships of nuclear and organelle DNA-dependent RNA polymerases. 3. Mechanisms of selective gene expression during organelle development and differentiation.